The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Ken Hargett1, Michael Bocci1, Krista Turner2, Margaret Berger1, Jose L. Rodriguez1; 1Respiratory Care Services, The Methodist Hospital, Houston, TX; 2Department of Surgery Division of Surgery Critical Care, The Methodist Hospital, Houston, TX

Background:Adaptive Support Ventilation (ASV) is a closed loop mode that automatically adjusts ventilator rate and pressure support to provide the patient with the combination of rate and tidal volume that result in the least work of breathing. The mode adjust support based on patient's inspiratory efforts and minute ventilation. ASV is a feature available on the Hamilton Medical G-5 ventilator. Our institution implemented a new fleet of Hamilton G5 ventilators and had the opportunity to evaluate the question whether ASV had an impact on ventilator duration. Methods:This was an observational study comparing ventilator duration in a large Surgical ICU before and after implementation of ASV. Previously Covidien PB 840 and Carefusion Avea ventilators were utilized. Ventilator management with the 840s and Aveas included aggressive daily spontaneous breathing trials. ASV was introduced in March 2011. In additional to automatic rate and VT adjustments, ASV utilizes a ventilation monitor display with user configurable parameters. Our configuration for extubation criteria includes FiO2 < .60, inspiratory pressure < 10cm, PEEP < 8cm, RSBI < 105, spontaneous breathing < 75%, minute ventilation < 14.2L . When a patient falls within the parameters,a timing window is displayed indicating patient readiness for extubation. The highly visible clock continues to be displayed so long as the patient remains within the acceptable parameters. Analysis utilizing measures of central tendency in univariate analysis was performed to determine arithmetic mean and normal distribution. A comparison of mean ventilator duration for the 3 month period prior to ASV implementation and the 3 months after implementation was performed. The patient population and other ventilator management strategies remained unchanged. Results:150 patients were ventilated in the baseline period. Mean ventilation duration was 84.80 hours. 141 patients were ventilated in the 3 month period after implementation of ASV. The mean ventilation duration decreased to 70.23 hours. The decrease in arithmetic mean ventilator duration was 14.57 hours or 16.6%. Conclusions:Daily spontaneous breathing trials provide a structured process to assist extubation decisions but sometimes may delay extubation until the following day. Automatic real time adjustments provided by ASV closed loop ventilation and a visual indicator of patient status has reduced ventilator duration in the Surgical Intensive Care Unit at our institution.
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